Multimode laser operation is usually characterized by high output power, yet its beam quality is inferior to that of a laser with single TEM00 mode operation. Here we present an efficient approach for improving the beam quality of multimode laser resonators. The approach is based on splitting the intra-cavity multimode beam into an array of smaller beams, each with a high quality beam distribut...

Cilex-Apollon is a high intensity laser facility delivering at least 5 PW pulses on targets at one shot per minute, to study physics such as laser plasma electron or ion accelerator and laser plasma X-Ray sources. Under construction, Apollon is a four beam laser installation with two target areas. To control the laser beam characteristics and alignment, more than 75 CCD cameras and 100 motors a...

We are developing Laser Super Cavity for compact X-ray generator based on Inverse Compton Scattering with several tens MeV electron beam. The laser supercavity increases the laser power and makes small laser beam size at the collision point with the electron beam. A FabryPerot cavity as the laser supercavity has been tested at the KEK-ATF (Accelerator Test Facility) and the design for the incre...

We studied proton beam production from a laser ion source using hydrogen rich target materials. In general, gas based species are not suitable for laser ion sources since formation of a dense laser target is difficult. In order to achieve reliable operation, we tested hydride targets using a sub nanosecond Q-switched Nd-YAG laser, which may help suppress target material consumption. We detected...

We report on the first laser cooling of a bunched beam of multiply charged C ions performed at the ESR (GSI) at a beam energy of E = 1.47GeV. Moderate bunching provided a force counteracting the decelerating laser force of one counterpropagating laser beam. This versatile type of laser cooling lead to longitudinally space-charge dominated beams with an unprecedented momentum spread of ∆p/p ≈ 10...

The optical nonlinearity and excited carrier lifetime in Ge nanocrystals (nc-Ge) embedded in a silica matrix have been investigated by means of single beam z scan and pump-probe techniques with laser pulse duration of 35 ps and 532 nm wavelength. The nc-Ge samples were prepared using magnetron cosputtering and postgrowth annealing at 800 °C. The nonlinear absorption coefficient a2 and refractiv...

It is very interesting that the enhanced peaks near 1150 and 1550 nm are observed in the photoluminescence (PL) spectra in the quantum system of Si-Ge nanolayer structure, which have the emission characteristics of a three-level system with quantum dots (QDs) pumping and emission of quasi-direct-gap band, in our experiment. In the preparing process of Si-Ge nanolayer structure by using a pulsed...

Nano-fabrication technologies for patterned structures made from thin films are reviewed. A classification is made to divide the patterning technologies in two groups namely with and without the using a mask. The more traditional methods as well as a few new methods are discussed al in relation with the application. As mask less methods we discussed direct patterning with ions including FIB, na...